This study develops specific facts about the nature of the Black English "lingua franca" which formed on the American eastern seaboard in the last half of the eighteenth century. Accepting an assumption that American English of this period was levelling into a "koine," this investigation attempts to characterize the consonant loss and substitution within a Black English koine which emerged parallel to that in the white dialect. Evidence for the consonant phonology is taken from the dialect spoken by black characters in American plays and novels of the period 1771-1836. Next, a modelling based on the work of Turner (1949) reconstructs the possible types of consonant loss and substitution which may have been patterned upon the sound systems of those major West African languages serving as input to the emerging American Black English koine. A correlation is drawn between the rules in consonant phonology in the koine and the attitudes, generally negative, of early modern British and American Grammarians toward these types of consonant loss and substitution. Thus, whether the consonant forms had sources in West Africa languages or in early modern British and American English, the Black English koine in its earliest period was stigmatized through negative attitudes on the part of white grammarians. (Author/AMH)